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Collective variable components (basis functions)

Each colvar is defined by one or more components (typically only one). Each component consists of a keyword identifying a functional form, and a definition block following that keyword, specifying the atoms involved and any additional parameters (cutoffs, ``reference'' values, ...).

The types of the components used in a colvar determine the properties of that colvar, and which biasing or analysis methods can be applied. In most cases, the colvar returns a real number, which is computed by one or more instances of the following components:

Some components do not return scalar, but vector values. They can only be combined with vector values of the same type, except within a scripted collective variable.

In the following, all the available component types are listed, along with their physical units and the limiting values, if any. Such limiting values can be used to define lowerBoundary and upperBoundary in the parent colvar.

For each type of component, the available configurations keywords are listed: when two components share certain keywords, the second component simply references to the documentation of the first regarding that keyword. The keywords that are available for all types of components are listed at the end (see



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